Removing contaminants from cigarette smoke



Jan. 28, 1969 R. v. LLOYD 3,424,168

REMOVING CONTAMINANTS FROM CIGARETTE SMOKE Filed NOV. 21, 1966 INVENTOR Eff/E VIZSOKD United States Patent 6 Claims ABSTRACT OF THE DISCLOSURE Activated carbon is impregnated with Benedicts solution or the potassium analog thereof to make a tobacco smoke filter. The product does a better job of removing FIGURE 1 there is provided a filter tip cigarette designated generally at 2. This cigarette includes a tobacco section 4 and a filter section 6 of particulate activated carbon impregnated with Benedicts solution. The cigarette has a conventional external paper wrapper 8.

Referring to FIGURE 2 the cigarette indicated generally at 10 includes a tobacco section 12 a first filter 14 of particulate activated carbon impregnated with Benedicts solution and a second filter 16 composed of fibers, e.g. a conventional cellulose acetate tow. The entire cigarette is wrapped in apaper 18 as is well known in the art. Thus 7 there is provided a smoking means comprising tobacco to acetaldehyde from smoke than does activated carbon alone, particularly in the range of 0.17 to 0.33 ml. of Benedicts solution per gram of activated carbon.

The present invention relates to a tobacco smoke filter.

Activated carbon has been employed for sometime as a tobacco smoke filter. However, it does not do a completely effective job of removing certain components such as acetaldehyde.

Cigarette smoke has ciliastatic components. These attack the cilia of the respiratory tract and retard the sweeping action. One of these ciliastatic components is acetaldehyde. It paralyzes the cilia for a short period of time. Accordingly it is believed to be beneficial to health to remove or keep at a minimum acetaldehyde and similar components present in tobacco smoke.

Accordingly it is an object of the present invention to prepare tobacco smoke filters which will remove acetaldehyde from the smoke.

Another object is to prepare cigarettes having improved activated carbon filters.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

It has now been found that these objects can be attained by impregnating activated carbon with Benedicts solution and using the impregnated activated carbon particles as a filter for tobacco smoke.

While the impregnated carbon of the present invention is of primary interest in connection with cigarette filters it also is useful as a filterfor pipes and cigars. The impregnated carbon particles can be the sole filter in cigarette, cigar or pipe or other filters can be employed in conjunction therewith. Thus there can be used a fibrous filter such as a conventional cellulose acetate tow, cotton fibers, viscose fibers, nylon fibers, polyethylene terephthalate and other polyester fibers, polyurethane fibers, polyethylene fibers, polypropylene fibers, etc. There also can be incorporated other particulate filters such as cation exchange and anion exchange resins, silica gel, etc.

The invention will be understood best in connection with the drawings wherein:

FIGURE 1 is a longitudinal view partially broken away in section of a cigarette constructed in accordance with the invention, and

FIGURE 2 is a longitudinal view partially broken away in section of a cigarette in an alternative embodiment of the invention.

Referring more specifically to the drawings as shown in be ignited and a filter of Benedicts solution impregnated carbon between the smoker and the tobacco.

Benedicts solution is composed of 17.3'grams of cupric sulfate pentahy-drate, 173 grams of sodium citrate dihydrate and 100 grams of sodium carbonate dissolved in sutlicient water to make a total volume of one liter.

In practice the activated carbon is impregnated with the Benedicts solution and then the Water is removed by drying, e.g. at 100 C. for 16 hours, prior to inclusion of the impregnated carbon in the cigarette.

In place of Benedicts solution there can be employed the analog where the sodium citrate is replaced by potas-' sium citrate and the sodium carbonate is replaced by potassium carbonate. v

Any of the conventional activated carbons can be em ployed such as Pittsburgh type CAL (18, x 20 mesh) and Pittsburgh type BPL, Darco activated carbons, Columbia activated carbon Grade SxAC. Granular activated carbons are preferred. The carbon can have a particle size of 10 to 200 mesh.

To test the effectiveness of the Benedicts solution impregnated activated carbon for the removal of acetaldehyde the following experiments were carried out.

Benedicts solution was prepared in the following manner. First 173 grams of sodium citrate dihydrate and 100 grams of anhydrous sodium carbonate were dissolved in 800 ml. of hot C.) distilled water. Then 17.3 grams of copper sulfate pentahydrate was dissolved in ml. of distilled Water. Next these solutions were mixed and diluted with distilled water to a volume of one liter.

The Benedicts solution thus prepared was used as a stock solution to impregnate 100 gram portions of activated carbon. In each case the total volume of impregnating solution was 100 ml. Dosages of active ingredient applied to the carbon were regulated by varying the volume of Benedicts solution in the total volume of liquid as shown in Table 1.

After the activated carbon was impregnated with the Benedicts solution (or diluted Benedicts solution in samples 2-5) the samples were dried sixteen hours at 100 C. I

A test was designed for acetaldehyde removal using an 0.28 cc. sample 18 x 20 mesh U.S. Sieve series activated carbon (10 mm. bed depth in 6 mm. diameter column). Acetaldehyde at a concentration of 0.36% in nitrogen was passed through the various Benedicts solution impregnated activated carbon samples at 100 ml. per minute measured at ambient temperature. The efiluent gas was analyzed with the hydrogen flame detector on an F & M-l609 Gas Chromatograph. The time to 80% breakthrough for various dosages of Benedicts solution impregnated carbon is set forth in Table 2.

The maximum elfectiveness of the Benedicts solution in removal of acetaldehyde occurs at a dosage level of between 0.17 and 0.33 ml./gram of activated carbon. However, this can be widely varied. Thus there can be used, 0.01 ml. to ml. of Benedicts solution per gram of activated carbon followed by drying of the impregnated carbon.

What is claimed is:

1. In a smoking means of the type where a quantity of tobacco is ignited and smoke is drawn therefrom by a smoker, the improvement which comprises a filter means interposed between the smoker and the tobacco, said filter means comprising activated carbon impregnated with Benedicts solution or the potassium analog thereof wherein the impregnated carbon contains 0.01 to 10 ml. of the Benedicts solution or the potassium analog thereof, per gram of activated carbon.

2. A smoking means according to claim 1 wherein the filter means comprises activated carbon particles impregnated with Benedicts solution.

3.,A, smoking means according, to claim .2.,which is a cigarette.

4. A cigarette according to claim 3 wherein there is employed 0.08 to 0.66 ml. of Benedicts solution per gram of activated carbon.

5. A cigarette according to claim 3 wherein there is employed 0.08 to 0.33 ml. of Benedicts solution per gram of activated carbon.

6. A cigarette according to claim 5 wherein there is employed 0.17 to 0.33 ml. of Benedicts solution per gram of activated carbon.

References Cited UNITED STATES PATENTS 3,251,365 5/1966 Keith et a1. 13110.9 X

FOREIGN PATENTS 650,633 10/1962 Canada.

682,930 11/1952 Great Britain.

OTHER REFERENCES U.S. Surgeon General, Smoking and Health US. Dept. H.E.W., Jan. 28, 1964, QP981 T6U5, pp. 61.

Brewster and McGwen, Organic Chemistry, 3rd ed., 1961, Prentice-Hall Inc. pp. 194-195.

SAMUEL KOREN, Primary Examiner.

US. Cl. X.R. 131--267, 265, 10.7 

